The present invention relates to nuclear magnetic resonance (NMR) imaging and spectroscopy and, more particularly, to novel methods for suppression of water, and other non-coupled-spin, resonance response signals by utilizing homonuclear polarization transfer techniques.
Nuclear magnetic resonance (NMR) imaging and spectroscopy presently appear to hold great promise for medical diagnostic purposes. The hydrogen (.sup.1 H) nucleus is perhaps the most readily observed, in present NMR imaging, due to its high gyromagnetic ratio and natural abundance. Most of the large amount of .sup.1 H nuclei, in biological systems, are contained in water molecules. Therefore, it is considerably easier to measure the amount, spin-lattice relaxation time T.sub.1 and spin-spin relaxation time T.sub.2 of water in biological systems, then to measure the amount, T.sub.1 and T.sub.2 of other .sup.1 H containing molecular species. While the observation of the natural-occurring concentration of metabolites is well within the capability of modern NMR imaging systems, the response signals from excited water molecules prove to be so intense, in practice, as to render other response signals substantially unobservable. Therefore, it is highly desirable to selectively eliminate the response signals from .sup.1 H nuclei in water, to allow the much smaller-amplitude response signals from other .sup.1 H molecules, arising from important components in biological samples, to be readily observed.